A method for electrochemical synthesis of chlorobromide

Abstract

The present invention relates to a method for electrochemically synthesizing chlorobromides. Specifically, under the action of an electric current, tetrabutylammonium bromide and hexachloroethane are used to generate two different halogen intermediates, which react with olefins to obtain chlorobromides. The present invention utilizes an inexpensive and readily available halogen source to produce a series of chlorobromides with high selectivity under simple and mild conditions.

Description

Technical Field

[0001] The present invention relates to a method for electrochemically synthesizing chlorobromide. Background Art

[0002] Organohalides are an important class of compounds, ubiquitous in commodity chemicals, pharmaceuticals, pesticides, and over 5,000 natural products. Furthermore, organohalides often serve as synthetic intermediates, participating in nucleophilic substitutions, free radical-mediated exchanges, and various cross-coupling reactions. These chemical transformations allow halogen-containing carbon atoms to serve as handles for precisely forging new C-C and C-heteroatom bonds. Bromochlorides are a significant subset of organohalides, exhibiting unique reactivity. Furthermore, bromochlorides containing two different halogen atoms can be introduced into two distinct molecular fragments through stepwise reactions, greatly enhancing the diversity and flexibility of molecular synthesis. Therefore, the development of efficient and highly selective methods for the synthesis of chlorobromides is urgently needed. Traditional methods generally involve the reaction of an activated halogen source (such as N-bromosuccinimide and thionyl chloride) with an olefin in the presence of a catalyst to produce chlorobromides. The use of activated halogen sources inevitably leads to high production costs, safety issues, and environmental concerns. Based on this, we have developed an electrically driven method for synthesizing chlorobromides using non-activated halogen sources (tetrabutylammonium bromide and hexachloroethane). This method primarily involves the conversion of two different non-activated halogen sources into two differently active halogen intermediates via paired electrolysis. These intermediates then react with alkenes to generate the chlorobromides with high chemo-, regio-, and diastereoselectivity. Furthermore, this method is extremely mild, requires no catalysts or additives, and is compatible with a wide range of functional groups.

[0003] In summary, this result describes a method for synthesizing a high-value-added chlorobromide with high selectivity by innovatively utilizing a non-activated halogen source and olefin reaction under electric drive. Summary of the Invention

[0004] The object of the present invention is to provide a method for electrochemically synthesizing chlorobromide.

[0005]

[0006] Reaction equation 1: Chlorobromination of olefins

[0007] The specific operation steps are as follows (reaction equation 1):

[0008] Under nitrogen atmosphere and / or air atmosphere, olefin 1, bromine source, chlorine source and solvent were added to a three-necked reaction flask equipped with electrodes, and the reaction was carried out at room temperature for 16 hours. After the reaction was completed, chlorobromide 2 was separated.

[0009] Bromine source is nBu4NBr (tetrabutylammonium bromide); the amount of bromine source used is 1.0-2.0 molar equivalents of the amount of olefin 1, preferably 1.5 molar equivalents.

[0010] The chlorine source is C2Cl6 (hexachloroethane); the amount of the chlorine source used is 1.0-2.0 molar equivalents of the amount of olefin 1, preferably 1.5 molar equivalents.

[0011] The solvent is dichloromethane, and the preferred volume is 5.0 mL.

[0012] The graphite electrode is the anode; the platinum electrode is the cathode; the current is 3.0-5.0 mA, preferably 4.5-5.0 mA.

[0013] Reaction temperature is 15-30℃

[0014] The present invention is driven by electric current to produce olefins, n Bu4NBr reacts with C2Cl6 to give chlorobromide.

[0015] The present invention starts from cheap and readily available raw materials and obtains a series of chlorobromides driven by green energy.

[0016] The present invention has the following advantages:

[0017] First, the use of electrical energy to drive the reaction makes it greener and more sustainable. Second, the reaction is carried out at room temperature, which makes the reaction conditions simple and mild. n Non-activated halogen sources such as Bu4NBr and C2Cl6 are safe and inexpensive. Finally, the resulting chlorobromides have high added value and have broad application prospects in the field of organic synthesis. DETAILED DESCRIPTION

[0018] In order to better understand the present invention, the following examples are provided for illustration. The reaction materials and results of Examples 1-28 are shown in Table 1.

[0019] Table 1 Reaction results of different olefin substrates

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] Example 1

[0026] The reaction was carried out in a reaction vessel equipped with a cathode and an anode. The anode and cathode were placed opposite each other with a distance of 2 cm. The cathode and anode were immersed in the reaction solution to a depth of 10 mm. A current was applied between the cathode and anode in the reaction system. A cylindrical graphite electrode with a diameter of 6 mm served as the anode; a platinum electrode with a length * width * thickness = 10 mm * 10 mm * 0.3 mm was the cathode. The current was 5.0 mA. Under a nitrogen atmosphere, olefin 1a (0.20 mmol), n Bu4NBr (0.30 mmol), C2Cl6 (0.30 mmol), and dichloromethane (5.0 mL) were reacted at room temperature at a current of 5.0 mA for 16 hours. After the reaction, chlorobromide 2a was obtained by column chromatography with a yield of 85%. The structure of the compound was identified by nuclear magnetic resonance (H and C spectroscopy).

[0027] The test data is as follows:

[0028]

[0029] (2-Bromo-1-chloroethyl)benzene(2a):colorless oil,known compound,37.5mg,85%yield,R f =0.9 (petroleum ether). 1 H NMR (700MHz, CDCl3) δ7.44–7.35(m,5H),5.06(dd,J=8.9,6.2Hz,1H),3.91(dd,J=10.4,6.2Hz,1H),3.84(dd,J=10.4,8.8Hz,1H); 13 C NMR (100MHz, CDCl3) δ138.41,129.20,128.83,127.36,61.36,35.96.

[0030] Example 2:

[0031] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The yield of product 2b was 86%, and the compound was identified by H and C NMR.

[0032]

[0033] 1-(2-Bromo-1-chloroethyl)-4-methylbenzene(2b): colorless oil, known compound, 40.4 mg, 86% yield, R f =0.3(petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.30(d,J=8.2Hz,2H),7.21(d,J=7.9Hz,2H),5.05(dd,J=8.8, 6.2Hz, 1H), 3.91 (dd, J=10.4, 6.2Hz, 1H), 3.83 (dd, J=10.3, 8.8Hz, 1H), 2.38 (s, 3H); 13 C NMR (100MHz, CDCl3) δ139.21,135.47,129.53,127.24,61.33,35.99,21.27.

[0034] Example 3:

[0035] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2c was 74%. The compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0036]

[0037] 4-(2-Bromo-1-chloroethyl)phenyl acetate(2c):colorless oil,41.2mg,74%yield,R f =0.2(petroleum ether / ethyl acetate=10:1). 1 H NMR (400MHz, CDCl3) δ7.46–7.37(m,2H),7.17–7.08(m,2H),5.05(dd,J=8.7,6.2 Hz, 1H), 3.88 (dd, J=10.5, 6.2Hz, 1H), 3.79 (dd, J=10.5, 8.7Hz, 1H), 2.31 (s, 3H); 13 C NMR (100MHz, CDCl3) δ169.21,151.06,135.88,128.56,121.97,60.70,35.94,21.19.HRMS Calculated for C 10 H 11 BrClO2[M+H]+ 276.9625, found 276.9627.

[0038] Example 4:

[0039] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2d was 68%, and the compound's structure was identified by H-NMR and C-NMR and high-resolution mass spectrometry.

[0040]

[0041] 4-(2-Bromo-1-chloroethyl)phenyl tert-butyl carbonate(2d):colorlessoil,45.8mg,68%yield,R f =0.5(petroleum ether / ethyl acetate=8:1). 1 H NMR (400MHz, CDCl3) δ7.44–7.38(m,2H),7.24–7.17(m,2H),5.05(dd,J=8.7,6.2 Hz,1H),3.87(dd,J=10.4,6.1Hz,1H),3.78(dd,J=10.4,8.7Hz,1H),1.56(s,9H); 13 C NMR(100MHz, CDCl3)δ151.58,151.45,135.81,128.51,121.64,83.89,60.65,35.87,27.70.HRMSCalculated for C 13 H 16 BrClNaO3[M+Na] + 356.9864, found 356.9860.

[0042] Example 5:

[0043] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 6.0 mA. The yield of product 2e was 72%, and the compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0044]

[0045] Methyl 4-(2-bromo-1-chloroethyl)benzoate(2e):colorless oil,40.1mg,72%yield,R f =0.6(petroleum ether / ethyl acetate=10:1). 1 H NMR (400MHz, CDCl3) δ8.06 (d, J=8.4Hz, 2H), 7.48 (d, J=8.4Hz, 2H), 5.08 (dd, J= 9.1,5.8Hz,1H),3.92(s,3H),3.91–3.87(m,1H),3.80(dd,J=10.4,9.1Hz,1H); 13 C NMR (100MHz, CDCl3) δ166.41,143.05,130.87,130.09,127.53,60.24,52.33,35.36.HRMS Calculated for C 10 H 11 BrClO2[M+H] + 276.9625,found276.9626.

[0046] Example 6:

[0047] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The yield of product 2f was 75%, and the compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0048]

[0049] 4-(2-Bromo-1-chloroethyl)-1,1'-biphenyl(2f):white solid,meltingpoint:94–95℃,44.3mg,75%yield,R f =0.4 (petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.66–7.57(m,4H),7.52–7.43(m,4H),7.43–7.34(m,1H),5.12 (dd,J=8.8,6.1Hz,1H),3.95(dd,J=10.4,6.2Hz,1H),3.88(dd,J=10.4,8.8Hz,1H); 13C NMR (100MHz, CDCl3) δ142.15,140.29,137.29,128.90,127.83,127.73,127.58,127.19,61.14,35.85.HRMS Calculated for C 14 H 12 BrCl[M] + 293.9805, found 293.9806.

[0050] Example 7:

[0051] The operation process and conditions were the same as in Example 1, except that the olefin compound described in Table 1 was different and the operating current was 4.0 mA. 2 g of product was obtained, with a yield of 65%. The compound was identified by H, F, and C NMR.

[0052]

[0053] 1-(2-Bromo-1-chloroethyl)-4-fluorobenzene(2g):colorless oil,known compound,30.8mg,65%yield,R f =0.8 (petroleum ether). 1 H NMR (700MHz, CDCl3) δ7.43–7.36(m,2H),7.12–7.04(m,2H),5.04(dd,J=9.2,5.8Hz,1H),3.90(dd,J=10.5,5.8Hz,1H),3.78(dd,J=10.5,9.2Hz,1H); 13 C NMR (175MHz, CDCl3) δ162.92 (d, J = 248.8Hz), 134.27 (d, J = 3.5Hz), 129.22 (d, J = 8.8Hz), 115.81 (d, J = 22.1Hz), 60.36, 35.80; 19 F NMR (375MHz,CDCl3)δ-111.92.

[0054] Example 8:

[0055] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The product yield was 78% in 2 h, and the compound was identified by H and C NMR.

[0056]

[0057] 1-Bromo-4-(2-bromo-1-chloroethyl)benzene(2h): colorless oil, known compound, 46.7 mg, 78% yield, R f =0.8 (petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.56–7.50(m,2H),7.31–7.26(m,2H),5.01(dd,J=9.2,5.8Hz,1H),3.88(dd,J=10.4,5.8Hz,1H),3.77(dd,J=10.4,9.2Hz,1H); 13 C NMR (100MHz, CDCl3) δ137.41,132.01,129.07,123.24,60.29,35.48.

[0058] Example 9:

[0059] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The yield of product 2i was 93%, and the compound was identified by H and C NMR.

[0060]

[0061] 1-(2-Bromo-1-chloroethyl)-4-chlorobenzene(2i): colorless oil, known compound, 47.2 mg, 93% yield, R f =0.8 (petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.42–7.31(m,4H),5.03(dd,J=9.2,5.8Hz,1H),3.89(dd,J=10.4,5.8Hz,1H),3.78(dd,J=10.4,9.2Hz,1H); 13 C NMR (100MHz, CDCl3) δ136.91,135.06,129.07,128.81,60.29,35.62.

[0062] Example 10:

[0063] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2j was 87%, and the compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0064]

[0065] 1-(2-Bromo-1-chloroethyl)-3-chlorobenzene(2j): colorless oil, 46.1 mg, 87% yield (the yield of the product has been adjusted accordingly), R f =0.8 (petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.42(s,1H),7.39–7.26(m,3H),5.01(dd,J=9.0,5.9Hz,1H),3.88(dd,J=10.5,5.9Hz,1H),3.78(dd,J=10.5,9.0Hz,1H); 13 C NMR(100MHz, CDCl3)δ140.32,134.69,130.09,129.40,127.65,125.68,60.23,35.53.HRMSCalculated for C8H7BrCl2[M] + 251.9103, found 251.9108.

[0066] Example 11:

[0067] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of the product 2k was 67%, and the compound was identified by H and C NMR and high-resolution mass spectrometry.

[0068]

[0069] 1-(2-Bromo-1-chloroethyl)-2-chlorobenzene(2k): colorless oil, 37.3 mg, 67% yield (the yield of the product has been adjusted accordingly), R f =0.8 (petroleum ether). 1H NMR (400MHz, CDCl3) δ7.58(dd,J=7.7,1.8Hz,1H),7.41(dd,J=7.8,1.6Hz,1H),7.28-7.37(m,2H),5.66(dd,J=7.8,6.6Hz,1H),3.94–3.84(m,2H).; 13 CNMR(100MHz, CDCl3)δ135.83,133.45,130.19,130.17,130.09,129.88,128.59,128.42,127.57,127.50,56.88,46.46,46.45,34.91.HRMSCalculated for C8H7BrCl2[M] + 251.9103, found 251.9108.

[0070] Example 12:

[0071] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 6.0 mA. The yield of product 21 was 58%, and the structure of the compound was identified by H and C NMR.

[0072]

[0073] 2-(2-Bromo-1-chloroethyl)pyridine(2l): colorless oil, known compound, 26.8mg, 58% yield (the yield of the product has been adjusted accordingly), R f =0.3(petroleum ether / ethyl acetate=8:1). 1 H NMR (400MHz, CDCl3) δ8.65(d,J=3.9Hz,1H),7.73(td,J=7.7,1.8Hz,1H),7.42(d,J=7.8Hz,1H),7.28(ddd,J= 7.6,4.8,1.2Hz,1H),5.15(dd,J=8.9,5.3Hz,1H),4.18(dd,J=10.1,8.9Hz,1H),3.92(dd,J=10.1,5.3Hz,1H); 13 C NMR (100MHz, CDCl3) δ156.49,149.87,137.02,123.79,123.05,60.62,34.26.

[0074] Example 13:

[0075] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The yield of product 2m was 73%. The compound was identified by H and C NMR and high-resolution mass spectrometry.

[0076]

[0077] 5-(2-Bromo-1-chloroethyl)-4-methylthiazole(2m):light yellow oil,35.2mg,73%yield,R f =0.1(petroleum ether / ethyl acetate=10:1). 1 H NMR (400MHz, CDCl3) δ8.76 (s, 1H), 5.40 (ddd, J = 9.6, 5.4, 0.8Hz, 1H), 3.96 (dd, J = 10.4, 5.4Hz, 1H), 3.76 (dd, J = 10.4, 9.6Hz, 1H), 2.49 (s, 3H); 13 C NMR(100MHz, CDCl3)δ152.33,152.30,130.67,53.44,36.47,15.49.HRMS Calculated for C6H8BrClNS[M+H] + 239.9244,found239.9244.

[0078] Example 14:

[0079] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 3.0 mA. The yield of product 2n was 93%, and the compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0080]

[0081] 2-Bromo-1-chloroethyl benzoate(2n):colorless oil,49.1mg,93%yield,R f =0.5(petroleum ether / ethyl acetate=20:1). 1H NMR (400MHz, CDCl3) δ8.10 (dd, J=8.3, 1.4Hz, 2H), 7.68–7.60 (m, 1H), 7.54–7.45 (m, 2H), 6.80(dd,J=8.5,3.3Hz,1H), 3.92(dd,J=11.1,8.6Hz,1H), 3.85(dd,J=11.1,3.4Hz,1H); 13 C NMR (100MHz, CDCl3) δ163.92,134.18,130.22,128.69,128.23,80.71,32.99.HRMS Calculated for C9H8BrClO2[M] + 261.9391, found 261.9388.

[0082] Example 15:

[0083] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 3.0 mA. The yield of the product 2o was 87%, and the compound's structure was identified by H and C NMR and high-resolution mass spectrometry.

[0084]

[0085] 2-Bromo-1-chloroethyl dodecanoate(2o): colorless oil, 59.5 mg, 87% yield. 1 H NMR (400MHz, CDCl3) δ6.55(dd,J=8.1,4.0Hz,1H),3.78–3.66(m,2H),2.41(t,J=7.5Hz,2H),1.66(p,J=7.4Hz,2H),1.26(m,16H),0.87(t,J=6.7Hz,3H).; 13 HRMS Calculated for C 14 H 27 BrClO2[M+H] + 341.0877,found314.0881.

[0086] Example 16:

[0087] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 4.0 mA. The yield of product 2aa was 79%, and the compound was identified by H and C NMR.

[0088]

[0089] trans-2-Bromo-3-chloro-3-phenylpropan-1-ol (2aa): colorless oil, known compound, 39.5 mg, 79% yield, R f =0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR (700MHz, CDCl3) δ7.45–7.34(m,5H),5.19(d,J=10.1Hz,1H),4.54(ddd,J=10.1,4. 7,2.9Hz,1H),4.26(dd,J=12.6,4.7Hz,1H),4.15(dd,J=12.7,2.9Hz,1H),2.22(s,1H); 13 CNMR (175MHz, CDCl3) δ139.02,129.06,128.70,127.75,64.64,61.52,59.69.

[0090] Example 17:

[0091] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2ab was 72%, and the structure of the compound was identified by H and C NMR.

[0092]

[0093] trans-2-Bromo-3-chloro-3-(p-tolyl)propan-1-ol(2ab): colorless oil, known compound, 38.0mg, 72% yield, R f =0.3(petroleum ether / ethyl acetate=8:1). 1HNMR (400MHz, CDCl3) δ7.29(d,J=8.2Hz,2H),7.20(d,J=7.9Hz,2H),5.17(d,J=10.2Hz,1H),4.54(ddd,J=10.2,4.7,2 .9Hz,1H),4.25(ddd,J=11.9,6.9,4.7Hz,1H),4.15(ddd,J=12.6,6.2,2.9Hz,1H),2.38(s,3H),2.22(t,J=6.6Hz,1H); 13 C NMR (100MHz, CDCl3) δ139.06,136.14,129.43,127.61,64.71,61.51,59.88,21.31.

[0094] Example 18:

[0095] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2ac was 70%, and the compound's structure was identified by H, F, and C NMR spectra.

[0096]

[0097] trans-2-Bromo-3-chloro-3-(4-fluorophenyl)propan-1-ol(2ac):colorlessoil,known compound,37.4mg,70%yield,R f =0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.42–7.33(m,2H),7.04-7.11(m,2H),5.18(d,J=10.1Hz,1H),4.48(ddd,J=10.1,4.5 ,3.0Hz,1H),4.26(ddd,J=12.2,7.5,4.5Hz,1H),4.13(ddd,J=12.7,6.2,3.0Hz,1H),2.19(t,J=6.6Hz1H); 13 C NMR (100MHz, CDCl3) δ162.81 (d, J = 248.6Hz), 135.00 (d, J = 3.4Hz), 129.60 (d, J = 8.4Hz), 115.70 (d, J = 21.8Hz), 64.56, 60.60, 59.70; 19F NMR (375MHz,CDCl3)δ-112.08.

[0098] Example 19:

[0099] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2ad was 80%, and the compound was identified by H and C NMR.

[0100]

[0101] trans-2-Bromo-3-chloro-3-(4-chlorophenyl)propan-1-ol(2ad):colorlessoil,known compound,45.3mg,80%yield,R f =0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR(400MHz, CDCl3)δ7.40–7.30(m,4H),5.16(d,J=10.1Hz,1H),4.47(ddd,J=10.1,4.5,3.0Hz,1H), 4.25(ddd,J=12.2,7.4,4.4Hz,1H), 4.12(ddd,J=12.7,6.0,3.0Hz,1H), 2.23(dd,J=7.8,6.5Hz,1H); 13 C NMR (100MHz, CDCl3) δ137.58,134.88,129.17,128.93,64.49,60.50,59.33.

[0102] Example 20:

[0103] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2ae was 88%, and the compound was identified by H and C NMR.

[0104]

[0105] trans-2-Bromo-3-(4-bromophenyl)-3-chloropropan-1-ol(2ae):colorlessoil,known compound,57.8mg,88%yield,R f=0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.52–7.45(m,2H),7.27–7.21(m,2H),5.11(d,J=10.1Hz,1H),4.43(ddd,J=10.1,4.5 ,3.0Hz,1H),4.22(ddd,J=12.2,7.2,4.4Hz,1H),4.08(ddd,J=12.7,6.5,3.0Hz,1H),2.21(t,J=6.8Hz,1H); 13 C NMR (100MHz, CDCl3) δ138.08,131.89,129.47,123.08,64.47,60.54,59.22.

[0106] Example 21:

[0107] The operation process and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2af was 88%, and the compound's structure was identified by H, F, and C NMR.

[0108]

[0109] trans-2-Bromo-3-chloro-3-(3-fluorophenyl)propan-1-ol(2af):colorlessoil,known compound,47.3mg,88%yield,R f =0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.35(td,J=8.0,5.8Hz,1H),7.17(d,J=7.8Hz,1H),7.12(dt,J=9.5,2.1Hz,1H),7.09–7.03(m,1H),5.16(d,J=10.1H z,1H),4.47(ddd,J=10.1,4.5,2.9Hz,1H),4.26(ddd,J=12.2,7.4,4.5Hz,1H),4.12(ddd,J=12.6,6.2,2.9Hz,1H),2.23(t,J=7.0Hz,1H); 13C NMR (100MHz, CDCl3) δ162.66 (d, J = 247.1Hz), 141.37 (d, J = 7.5Hz), 130.24 (d, J = 8.4Hz), 123.6 1(d,J=3.0Hz), 116.11(d,J=21.1Hz), 114.86(d,J=22.5Hz), 64.44, 60.47(d,J=2.0Hz), 59.13; 19 F NMR (375MHz,CDCl3)δ-111.96.

[0110] Example 22:

[0111] The operation process and conditions were the same as in Example 1, except that the olefin compound described in Table 1 was different and the operating current was 5.0 mA. The yield of product 2ag was 93%, and the structure of the compound was identified by H and C NMR.

[0112]

[0113] trans-2-Bromo-3-chloro-3-(3-chlorophenyl)propan-1-ol(2ag): whitesolid, known compound, 52.8 mg, 93% yield, R f =0.5(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.53 (dd, J=7.8, 1.8Hz, 1H), 7.40 (dd, J=7.8, 1.6Hz, 1H), 7.31 (m, 2H), 5.77 (d,J=10.1Hz,1H),4.62(ddd,J=10.1,4.8,2.7Hz,1H),4.35–4.15(m,2H),2.26(t,J=7.0Hz,1H); 13 C NMR (100MHz, CDCl3) δ136.67,133.59,130.08,129.90,128.86,127.52,64.42,58.53,56.98.

[0114] Example 23:

[0115] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The product 2ah was obtained in 80% yield. The compound's structure was identified by H-NMR, F-NMR, and C-NMR and high-resolution mass spectrometry.

[0116]

[0117] trans-2-Bromo-3-chloro-3-(3-(trifluoromethyl)phenyl)propan-1-ol(2ah):white solid,melting point:56–57℃,50.6mg,80%yield,R f =0.4(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.66(s,1H),7.62(d,J=7.3Hz,1H),7.59(d,J=8.0Hz,1H),7.52(t,J=7.7Hz,1H),5.24(d,J= 10.1Hz,1H),4.50(ddd,J=10.1,4.4,3.0Hz,1H),4.29(m,1H),4.13(dt,J=12.4,3.4Hz,1H),2.25(t,J=6.2Hz,1H); 13 C NMR (100MHz, CDCl3) δ140.07, δ131.20, 131.10 (q, J = 32.7Hz), 129.25, 125.87 ( q, J=3.7Hz), 123.79 (d, J=272.5Hz), 124.75 (q, J=3.8Hz), 64.36, 60.31, 58.95; 19 F NMR(375MHz,CDCl3)δ-62.65.HRMS calculated for C 10 H9BrClF3O[M] + 315.9472,found315.9467.

[0118] Example 24:

[0119] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2ai was 85%, and the structure of the compound was identified by H and C NMR.

[0120]

[0121] trans-2-Bromo-3-(2-bromophenyl)-3-chloropropan-1-ol(2ai): white solid, known compound, 55.9 mg, 85% yield, R f =0.5(petroleum ether / ethyl acetate=4:1). 1 HNMR (400MHz, CDCl3) δ7.59(dd,J=8.1,1.3Hz,1H),7.53(dd,J=7.9,1.7Hz,1H),7.39(td,J=7.6,1.3Hz,1H),7.24–7.17(m,1H),5.77(d,J=1 0.0Hz,1H),4.60(ddd,J=9.8,4.7,2.6Hz,1H),4.25(ddd,J=12.3,7.3,4.9Hz,1H),4.18(ddd,J=12.8,6.4,2.7Hz,1H),2.24(t,J=7.0Hz,1H); 13 C NMR (100MHz, CDCl3) δ138.32,133.17,130.33,128.88,128.19,124.12,64.38,59.49,58.68.

[0122] Example 25:

[0123] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2aj was 70%, and the compound's structure was identified by H-NMR and C-NMR and high-resolution mass spectrometry.

[0124]

[0125] trans-2-Bromo-1-chloro-3-methoxypropyl)benzene(2aj):colorless oil,37.1mg,70%yield,R f =0.7(petroleum ether / ethyl acetate=10:1). 1 H NMR (400MHz, CDCl3) δ7.45–7.34(m,5H),5.25(d,J=8.9Hz,1H),4.56–4.48(m, 1H), 4.03 (dd, J=10.8, 4.6Hz, 1H), 3.81 (dd, J=10.9, 3.9Hz, 1H), 3.49 (s, 3H); 13C NMR (100MHz, CDCl3) δ138.65,128.94,128.52,127.96,73.74,61.67,59.31,55.10.HRMS Calculated for C 10 H 12 BrClO[M] + 261.9755,found261.9752.

[0126] Example 26:

[0127] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The product 2ak was obtained in a 90% yield. The compound was structurally identified by H and C NMR and high-resolution mass spectrometry.

[0128]

[0129] trans-2-Bromo-3-chloro-3-phenylpropyl acetate(2ak):white solid,52.3mg(10:1rr),90%yield,R f =0.3(petroleum ether / ethyl acetate=8:1),R f =0.8(petroleum ether / ethyl acetate=4:1). 1 H NMR (400MHz, CDCl3) δ7.43–7.34(m,5H),5.13(d,J=9.3Hz,1H),4.65(d,J=3.9Hz,2H),4.56(ddd,J=9.0,4.9,3.9Hz,1H),2.15(s,3H); 13 C NMR (100MHz, CDCl3) δ170.38,138.43,129.16,128.70,127.75,65.53,61.96,52.95,20.81.HRMS Calculated for C 11 H 12 BrClO2[M] + 289.9704, found 289.9705.

[0130] Example 27:

[0131] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 5.0 mA. The yield of product 2a1 was 84%. The compound was structurally identified by H-NMR and C-NMR and high-resolution mass spectrometry.

[0132]

[0133] trans-(2-Bromo-1,3-dichloropropyl)benzene(2al):white solid,meltingpoint:75–76℃,45.2mg,84%yield,R f =0.7 (petroleum ether). 1 H NMR (400MHz, CDCl3) δ7.51–7.40(m,5H),5.30(d,J=8.5Hz,1H),4.67(dt,J=8.8,4.5Hz,1H),4.30(dd,J=12.2,4.4Hz,1H),3.98(dd,J=12.2,4.6Hz,1H); 13 C NMR(100MHz, CDCl3)δ137.67,129.29,128.65,128.07,61.85,55.57,47.50.HRMS Calculated for C9H9BrCl2[M] + 265.9259,found 265.9254.

[0134] Example 28:

[0135] The operating procedures and conditions were the same as in Example 1, except that the olefin compounds listed in Table 1 were different and the operating current was 6.0 mA. The product 2am was obtained in a 65% yield, and its structure was identified by H and C NMR.

[0136]

[0137] (1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl4-(2-bromo-1-chloroethyl)benzoate(2al):colorless oil,52.1mg(1:1dr),65%yield,R f =0.6(petroleum ether / ethyl acetate=10:1). 1H NMR (400MHz, CDCl3) δ8.07(d,J=8.1Hz,2H),7.48(d,J=8.1Hz,2H),5.08(dd,J=9.2,5.8Hz ,1H),4.94(td,J=10.9,4.4Hz,1H),3.91(dd,J=10.4,5.8Hz,1H),3.81(t,J=9.8Hz,1H),2. 12(d,J=12.1Hz,1H),1.95(pd,J=7.0,2.5Hz,1H),1.73(d,J=11.4Hz,2H),1.55(ddt,J=15 .9,9.7,3.4Hz,2H),1.21–1.03(m,2H),0.92(dd,J=6.8,4.5Hz,7H),0.79(d,J=6.9Hz,3H); 13 C NMR (100MHz, CDCl3) δ165.37,142.82,131.62,130.07,127.44,75.1460.28,4 7.28,40.95,35.32,35.30,34.31,31.46,26.50,23.61,22.05,20.79,16.50.

[0138] Example 29:

[0139] The operation process and conditions were the same as those in Example 1, except that tetrachloroethane was used as the chlorine source. The yield of product 2a was 75%, and the structure of the compound was identified by H and C NMR.

[0140] Example 30:

[0141] The operation process and conditions were the same as those in Example 1, except that a glassy carbon electrode was used as the positive electrode. The yield of product 2a was 70%, and the structure of the compound was identified by nuclear magnetic resonance (H and C spectroscopy).

[0142] Example 31:

[0143] The operation process and conditions were the same as those in Example 1, except that the reaction was carried out in air (instead of nitrogen atmosphere). The yield of product 2a was 62%, and the structure of the compound was identified by H and C NMR.

[0144] Comparative Example 1:

[0145] The operation process and conditions were the same as those in Example 1, except that no current was passed. The target product 2a was not obtained.

[0146] Comparative Example 2:

[0147] The operation process and conditions were the same as those in Example 1, except that N-bromosuccinimide was used as the bromine source. The yield of product 2a was 19%, and the structure of the compound was identified by H and C NMR.

[0148] Comparative Example 3:

[0149] The operation process and conditions were the same as those in Example 1, except that methanol was used as the solvent. The yield of product 2a was 2%, and the structure of the compound was identified by H and C NMR.

[0150] Comparative Example 4:

[0151] The operation process and conditions were the same as those in Example 1, except that lead was used as the negative electrode. The yield of product 2a was 35%, and the structure of the compound was identified by nuclear magnetic resonance (H and C spectroscopy).

Claims

1. A method for electrochemically synthesizing chlorobromide, characterized in that: ， where R 1 is one of a phenyl, 4-methylphenyl, 4-acetoxyphenyl, 4-tert-butoxycarbonyloxyphenyl, 4-methoxycarbonylphenyl, 4-biphenylyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-menthol ester phenyl, 3-fluorophenyl, 3-chlorophenyl, 3-trifluoromethylphenyl, 2-chlorophenyl, 2-bromophenyl, pyridyl, 2-methylthiazolyl, benzoate or dodecyl ester group; R 2 is one of hydrogen, hydroxymethyl, chloromethyl, acetoxymethyl or methoxymethyl groups, Bromine source is n Bu4NBr tetrabutylammonium bromide, the chlorine source is C2Cl6 hexachloroethane or tetrachloroethane, the solvent is dichloromethane, the graphite electrode is the anode; the platinum electrode is the cathode; the current size is 3.0-5.0mA or 6.0 mA.

2. The method according to claim 1, characterized in that: The specific steps are as follows: Under nitrogen atmosphere and / or air atmosphere, olefin 1, bromine source, chlorine source and solvent are added to a three-necked reaction flask equipped with electrodes, and the reaction is carried out at 15-30°C for 8-16 hours. After the reaction is completed, chlorobromide 2 is separated.

3. The method according to claim 2, characterized in that: The electrochemical reaction time is 12-16 hours.

4. The method according to claim 2, characterized in that: The molar ratio of olefin 1, bromine source and chlorine source is 1.0:1.0~2.0:1.0~2.

0.

5. The method according to claim 4, characterized in that: The molar ratio of olefin 1, bromine source and chlorine source is 1.0:1.5~2.0:1.5~2.

0.

6. The method according to claim 2, characterized in that: The amount of solvent used is 4.0-10.0 mL relative to 0.2 mmol of olefin.

7. The method according to claim 6, characterized in that: The amount of solvent used is 4.0-6.0 mL relative to 0.2 mmol of olefin.

8. The method according to claim 2, characterized in that: The current size is 4.5 mA-5.0 mA.

9. The method according to claim 2, characterized in that: The reaction atmosphere was nitrogen.

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